Abdominal aortic aneurysm: contrast-enhanced US for missed endoleaks after endoluminal repair.

Abstract

To evaluate contrast material-enhanced ultrasonography (US) for depiction of endoleaks after endovascular abdominal aortic aneurysm repair (or endovascular aneurysm repair [EVAR]) in patients with aneurysm enlargement and no evidence of endoleak. From November 1998 to February 2003, 112 patients underwent EVAR. At follow-up, duplex US and biphasic multi-detector row computed tomographic (CT) angiography were performed. In 10 patients (group A), evident aneurysm enlargement was observed, with no evidence of complications, at both CT angiography and duplex US. Group A patients, 10 men (mean age, 69.6 years +/- 10 [standard deviation]), underwent US after intravenous bolus injection of a second-generation contrast agent, with continuous low-mechanical index (0.01-0.04) real-time tissue harmonic imaging. Group B patients, 10 men (mean age, 71.3 years +/- 8.2) with aneurysm shrinkage and no evidence of complications, and group C patients, 10 men (mean age, 73.2 years +/- 6) with CT angiographic evidence of endoleak, underwent contrast-enhanced US. Digital subtraction angiography (DSA) was performed in groups A and C. Endoleak detection and characterization were assessed with imaging modalities used in groups A-C; at contrast-enhanced US, time of detection of endoleak, persistence of sac enhancement, and morphology of enhancement were evaluated. In group A, contrast-enhanced US depicted one type I, six type II, one type III, and two undefined endoleaks that were not detected at CT angiography. All leakages were characterized by slow and delayed echo enhancement detected at longer than 150 seconds after contrast agent administration. DSA results confirmed findings in all patients; percutaneous treatment was performed. In group B, contrast-enhanced US did not show echo enhancement; in group C, results with this modality confirmed findings at CT angiography and DSA. Contrast-enhanced US depicts endoleaks after EVAR, particularly when depiction fails with other imaging modalities.